Automotive nitrous systems are calibrated around measurable pressure, fuel, jetting, and horsepower targets. The figures below come from Holley and NOS manuals, product pages, technical support material, and application charts; they are presented with their stated conditions and are not independent verification of legacy documentation.
Contents
- Bottle pressure and temperature
- Bottle capacity and operating details
- Fuel pressure and fuel supply
- 5.0L Ford kit horsepower and jetting
- LS1 kit settings
- Motorcycle fogger outputs
- Large-engine Crosshair systems
Bottle pressure and temperature
The Holley Nitrous Basics bottle temperature chart shows a steep relationship between bottle temperature and pressure. At -30°F, the listed pressure is 167 psi; at -20°F, it is 203 psi; and at -10°F, it is 240 psi. At 0°F, the chart lists 283 psi. These are chart values for the stated temperatures, not universal readings for every bottle or installation.
Pressure rises through the lower and middle part of the chart. The listed value is 335 psi at 10°F, 387 psi at 20°F, and 460 psi at 32°F. At 40°F, the chart reaches 520 psi, followed by 590 psi at 50°F and 675 psi at 60°F.
The same chart lists 760 psi at 70°F and 865 psi at 80°F. At 85°F, it lists 950 psi, while 97°F corresponds to 1,069 psi. NOS recommends 950 psi for optimum performance in the Holley Nitrous Basics material. That recommendation sits directly on the chart’s 85°F value, while the 97°F figure is higher than the recommended optimum.
| Bottle temperature | Listed bottle pressure |
|---|---|
| -30°F | 167 psi |
| 0°F | 283 psi |
| 32°F | 460 psi |
| 50°F | 590 psi |
| 70°F | 760 psi |
| 85°F | 950 psi |
| 97°F | 1,069 psi |
The Holley Motor Life nitrous bottle sizing article gives a recommended bottle-temperature window of 85°F to 95°F and a recommended operating pressure range of 900 psi to 1,000 psi. Holley NOS Technical Support gives another baseline target of 900 psi to 950 psi. These ranges overlap, but they should be kept attached to their named sources rather than treated as one universal specification.
Bottle capacity and operating details
The Holley Motor Life nitrous bottle sizing article states that a full bottle contains 10 lb of nitrous oxide. The same source specifies a siphon-tube bend of 30 to 40 degrees near the bottom of the bottle. Both figures describe hardware or capacity details, not a predicted elapsed run time.
Run time varies by kit and operating conditions. The Holley 5.0L Ford kit manual says that its standard #10 nitrous bottle supplies just under 1 minute of wide-open-throttle operation. That is a manual-specific duration for the stated kit and bottle configuration; it should not be generalized to every automotive nitrous system.
The pressure numbers also show why temperature is a central operating variable. The Holley chart moves from 760 psi at 70°F to 950 psi at 85°F, a 190-psi difference across those two listed points. From 85°F to 97°F, the listed pressure increases from 950 psi to 1,069 psi. Those comparisons are direct differences between chart entries, not estimates of a pressure curve between them.
Fuel pressure and fuel supply
Fuel-side requirements are stated separately from bottle pressure. For the carbureted Big Shot system, the Holley NOS Big Shot product page recommends a fuel-pump operating range of 5 psi to 10 psi. It also requires at least 0.1 gallons of gasoline per hour per horsepower at 6 psi.
The Holley NOS Technical Support material recommends racing fuel with an octane rating of 100 or more for higher-compression or higher-horsepower levels. This is an octane threshold attached to those conditions, not a claim that every nitrous application requires the same fuel.
The Holley Crosshair Plate System manual lists the same 5 psi to 10 psi carburetor fuel-pressure range for Crosshair systems. It requires at least 0.10 gallons of gasoline per hour per horsepower at 5 psi. Although the numerical flow requirement is written with two decimal places in that manual, it represents the same quantity as 0.1 gallons per hour per horsepower.
The separate pressure domains matter when comparing specifications: the bottle-side targets are commonly stated around 900 psi to 1,000 psi, while the carburetor fuel-side targets are 5 psi to 10 psi. They measure different parts of the system and should not be substituted for one another.
5.0L Ford kit horsepower and jetting
The Holley 5.0L Ford kit manual lists nine horsepower settings with paired nitrous/fuel jetting. The progression begins at 100 HP with 43/31 jetting and rises to 300 HP with 91/52 jetting. In the entries below, each pair is reported in the manual’s order as nitrous/fuel jets.
| Rated gain | Jetting listed by the manual |
|---|---|
| 100 HP | 43/31 |
| 125 HP | 52/33 |
| 150 HP | 59/37 |
| 175 HP | 65/40 |
| 200 HP | 71/42 |
| 225 HP | 76/45 |
| 250 HP | 81/47 |
| 275 HP | 86/51 |
| 300 HP | 91/52 |
At 125 HP, the manual lists 52/33 jetting; at 150 HP, it lists 59/37; and at 175 HP, it lists 65/40. The 200 HP setting is 71/42, the 225 HP setting is 76/45, and the 250 HP setting is 81/47. The final two entries are 86/51 for 275 HP and 91/52 for 300 HP.
These rows are application data from the 5.0L Ford kit manual, not a general formula for selecting jets on another engine. The manual’s separate bottle note says a standard #10 bottle supplies just under 1 minute of wide-open-throttle operation.
LS1 kit settings
The Holley LS1 kit manual identifies its application as 1997–2004 GM LS1 engines. It describes the kit as designed for 75 HP to 250 HP over stock and states that three jet combinations generate 100 HP, 125 HP, or 150 HP gains. The manual also recommends spark plugs gapped at 0.035 inch and requires bottle pressure between 900 psi and 1,000 psi during operation.
The manual provides four specific nitrous/fuel jet settings. The 75 HP setting uses a 41 nitrous jet and a 26 fuel jet, with NGK TR6 or Autolite 103 plugs. The 100 HP setting uses a 51 nitrous jet and a 31 fuel jet, with the same plug options.
For the 125 HP setting, the listed combination is a 55 nitrous jet and a 35 fuel jet. For the 150 HP setting, it is a 63 nitrous jet and a 38 fuel jet. Both entries are part of the LS1 kit’s application-specific table, and the source’s overall design range remains 75 HP to 250 HP over stock.
The distinction between the stated overall range and the listed combinations is important: the manual gives a 75 HP starting setting and identifies 100 HP, 125 HP, and 150 HP combinations, while separately describing the kit as designed for gains up to 250 HP over stock. The supplied manual figures do not provide additional jet pairs for every point in that wider range.
Motorcycle fogger outputs
The Holley Motorcycle Fogger Jetting sheet reports output by cylinder count as well as per-cylinder horsepower. Its first listed combination, 14/16/14 jetting, corresponds to 6 HP per cylinder, 12 HP on a 2-cylinder engine, and 24 HP on a 4-cylinder engine.
The sheet lists 16/18/16 jetting for 9 HP per cylinder. The corresponding totals are 18 HP on a 2-cylinder engine and 36 HP on a 4-cylinder engine. At 18/22/18 jetting, the chart gives 12 HP per cylinder, 24 HP on a 2-cylinder engine, and 48 HP on a 4-cylinder engine.
Its highest supplied row is 20/24/20 jetting: 15 HP per cylinder, 30 HP on a 2-cylinder engine, and 60 HP on a 4-cylinder engine.
| Jetting shown | Per cylinder | 2-cylinder total | 4-cylinder total |
|---|---|---|---|
| 14/16/14 | 6 HP | 12 HP | 24 HP |
| 16/18/16 | 9 HP | 18 HP | 36 HP |
| 18/22/18 | 12 HP | 24 HP | 48 HP |
| 20/24/20 | 15 HP | 30 HP | 60 HP |
These motorcycle figures are kept separate from the automotive kit data because the source is a motorcycle fogger chart and reports its outputs by cylinder configuration.
Large-engine Crosshair systems
The Holley Crosshair Plate System manual says NOS Crosshair plate systems are intended for engines of at least 450 CID. It gives adjustable power gains from 250 HP to 350 HP, establishing a 100-HP span between the listed lower and upper settings.
For the same system, the manual calls for carburetor fuel pressure of 5 psi to 10 psi and requires at least 0.10 gallons of gasoline per hour per horsepower at 5 psi. Those fuel-side requirements match the Crosshair-specific figures described earlier, while the 450-CID minimum and 250–350 HP adjustable range define the application scale.
Taken together, the source figures describe several distinct measurement layers: bottle temperature and pressure, fuel pressure and flow, jet combinations, rated horsepower, engine displacement, cylinder count, and spark-plug gap. Reading each number with its source, application, and measurement condition preserves the limits of the documentation and avoids treating one kit’s calibration as a universal automotive rule.